/**
 * Copyright 2018-2019 jianggujin (www.jianggujin.com).
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.jianggujin.modulelink.util;

import java.util.List;
import java.util.Map;

/**
 * 多值集合
 * 
 * @author jianggujin
 *
 * @param <K> 键类型
 * @param <V> 值类型
 */
public interface JMultiValueMap<K, V> extends Map<K, List<V>> {
    /**
     * 获得指定键值对应的首个值
     * 
     * @param key 键
     * @return 值集合中第一个
     */
    V getFirst(K key);

    /**
     * 添加
     * 
     * @param key   键
     * @param value 值
     */
    void add(K key, V value);

    /**
     * 设置
     * 
     * @param key   键
     * @param value 值
     */
    void set(K key, V value);

    /**
     * 设置
     * 
     * @param values 键值集合
     */
    void setAll(Map<K, V> values);

    /**
     * 转换为单值集合
     * 
     * @return 单值集合
     */
    Map<K, V> toSingleValueMap();

}
